sys/kern/kern_ktr.c

   1 /*
   2  * Copyright (c) 2005 The DragonFly Project.  All rights reserved.
   3  *
   4  * This code is derived from software contributed to The DragonFly Project
   5  * by Matthew Dillon <dillon@backplane.com>
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  *
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in
  15  *    the documentation and/or other materials provided with the
  16  *    distribution.
  17  * 3. Neither the name of The DragonFly Project nor the names of its
  18  *    contributors may be used to endorse or promote products derived
  19  *    from this software without specific, prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  22  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  23  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  24  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
  25  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  26  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
  27  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  28  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
  29  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  30  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  31  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  */
  34 /*
  35  * The following copyright applies to the DDB command code:
  36  *
  37  * Copyright (c) 2000 John Baldwin <jhb@FreeBSD.org>
  38  * All rights reserved.
  39  *
  40  * Redistribution and use in source and binary forms, with or without
  41  * modification, are permitted provided that the following conditions
  42  * are met:
  43  * 1. Redistributions of source code must retain the above copyright
  44  *    notice, this list of conditions and the following disclaimer.
  45  * 2. Redistributions in binary form must reproduce the above copyright
  46  *    notice, this list of conditions and the following disclaimer in the
  47  *    documentation and/or other materials provided with the distribution.
  48  * 3. Neither the name of the author nor the names of any co-contributors
  49  *    may be used to endorse or promote products derived from this software
  50  *    without specific prior written permission.
  51  *
  52  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  53  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  54  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  55  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  56  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  57  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  58  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  59  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  60  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  61  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  62  * SUCH DAMAGE.
  63  */
  64 /*
  65  * $DragonFly: src/sys/kern/kern_ktr.c,v 1.23 2008/02/12 23:33:23 corecode Exp $
  66  */
  67 /*
  68  * Kernel tracepoint facility.
  69  */
  70
  71 #include "opt_ddb.h"
  72 #include "opt_ktr.h"
  73
  74 #include <sys/param.h>
  75 #include <sys/cons.h>
  76 #include <sys/kernel.h>
  77 #include <sys/libkern.h>
  78 #include <sys/proc.h>
  79 #include <sys/sysctl.h>
  80 #include <sys/ktr.h>
  81 #include <sys/systm.h>
  82 #include <sys/time.h>
  83 #include <sys/malloc.h>
  84 #include <sys/spinlock.h>
  85 #include <sys/thread2.h>
  86 #include <sys/spinlock2.h>
  87 #include <sys/ctype.h>
  88
  89 #include <machine/cpu.h>
  90 #include <machine/cpufunc.h>
  91 #include <machine/specialreg.h>
  92 #include <machine/md_var.h>
  93
  94 #include <ddb/ddb.h>
  95
  96 #ifndef KTR_ENTRIES
  97 #define KTR_ENTRIES             2048
  98 #endif
  99 #define KTR_ENTRIES_MASK        (KTR_ENTRIES - 1)
 100
 101 /*
 102  * test logging support.  When ktr_testlogcnt is non-zero each synchronization
 103  * interrupt will issue six back-to-back ktr logging messages on cpu 0
 104  * so the user can determine KTR logging overheads.
 105  */
 106 #if !defined(KTR_TESTLOG)
 107 #define KTR_TESTLOG     KTR_ALL
 108 #endif
 109 KTR_INFO_MASTER(testlog);
 110 #if KTR_TESTLOG
 111 KTR_INFO(KTR_TESTLOG, testlog, test1, 0, "test1", sizeof(void *) * 4);
 112 KTR_INFO(KTR_TESTLOG, testlog, test2, 1, "test2", sizeof(void *) * 4);
 113 KTR_INFO(KTR_TESTLOG, testlog, test3, 2, "test3", sizeof(void *) * 4);
 114 KTR_INFO(KTR_TESTLOG, testlog, test4, 3, "test4", 0);
 115 KTR_INFO(KTR_TESTLOG, testlog, test5, 4, "test5", 0);
 116 KTR_INFO(KTR_TESTLOG, testlog, test6, 5, "test6", 0);
 117 #ifdef SMP
 118 KTR_INFO(KTR_TESTLOG, testlog, pingpong, 6, "pingpong", 0);
 119 KTR_INFO(KTR_TESTLOG, testlog, pipeline, 7, "pipeline", 0);
 120 #endif
 121 KTR_INFO(KTR_TESTLOG, testlog, crit_beg, 8, "crit_beg", 0);
 122 KTR_INFO(KTR_TESTLOG, testlog, crit_end, 9, "crit_end", 0);
 123 KTR_INFO(KTR_TESTLOG, testlog, spin_beg, 10, "spin_beg", 0);
 124 KTR_INFO(KTR_TESTLOG, testlog, spin_end, 11, "spin_end", 0);
 125 #define logtest(name)   KTR_LOG(testlog_ ## name, 0, 0, 0, 0)
 126 #define logtest_noargs(name)    KTR_LOG(testlog_ ## name)
 127 #endif
 128
 129 MALLOC_DEFINE(M_KTR, "ktr", "ktr buffers");
 130
 131 SYSCTL_NODE(_debug, OID_AUTO, ktr, CTLFLAG_RW, 0, "ktr");
 132
 133 int             ktr_entries = KTR_ENTRIES;
 134 SYSCTL_INT(_debug_ktr, OID_AUTO, entries, CTLFLAG_RD, &ktr_entries, 0, "");
 135
 136 int             ktr_version = KTR_VERSION;
 137 SYSCTL_INT(_debug_ktr, OID_AUTO, version, CTLFLAG_RD, &ktr_version, 0, "");
 138
 139 static int      ktr_stacktrace = 1;
 140 SYSCTL_INT(_debug_ktr, OID_AUTO, stacktrace, CTLFLAG_RD, &ktr_stacktrace, 0, "");
 141
 142 static int      ktr_resynchronize = 0;
 143 SYSCTL_INT(_debug_ktr, OID_AUTO, resynchronize, CTLFLAG_RW, &ktr_resynchronize, 0, "");
 144
 145 #if KTR_TESTLOG
 146 static int      ktr_testlogcnt = 0;
 147 SYSCTL_INT(_debug_ktr, OID_AUTO, testlogcnt, CTLFLAG_RW, &ktr_testlogcnt, 0, "");
 148 static int      ktr_testipicnt = 0;
 149 static int      ktr_testipicnt_remainder;
 150 SYSCTL_INT(_debug_ktr, OID_AUTO, testipicnt, CTLFLAG_RW, &ktr_testipicnt, 0, "");
 151 static int      ktr_testcritcnt = 0;
 152 SYSCTL_INT(_debug_ktr, OID_AUTO, testcritcnt, CTLFLAG_RW, &ktr_testcritcnt, 0, "");
 153 static int      ktr_testspincnt = 0;
 154 SYSCTL_INT(_debug_ktr, OID_AUTO, testspincnt, CTLFLAG_RW, &ktr_testspincnt, 0, "");
 155 #endif
 156
 157 /*
 158  * Give cpu0 a static buffer so the tracepoint facility can be used during
 159  * early boot (note however that we still use a critical section, XXX).
 160  */
 161 static struct   ktr_entry ktr_buf0[KTR_ENTRIES];
 162
 163 __cachealign struct ktr_cpu ktr_cpu[MAXCPU] = {
 164         { .core.ktr_buf = &ktr_buf0[0] }
 165 };
 166
 167 #ifdef SMP
 168 static int      ktr_sync_state = 0;
 169 static int      ktr_sync_count;
 170 static int64_t  ktr_sync_tsc;
 171 #endif
 172 struct callout  ktr_resync_callout;
 173
 174 #ifdef KTR_VERBOSE
 175 int     ktr_verbose = KTR_VERBOSE;
 176 TUNABLE_INT("debug.ktr.verbose", &ktr_verbose);
 177 SYSCTL_INT(_debug_ktr, OID_AUTO, verbose, CTLFLAG_RW, &ktr_verbose, 0, "");
 178 #endif
 179
 180 static void ktr_resync_callback(void *dummy __unused);
 181
 182 extern int64_t tsc_offsets[];
 183
 184 static void
 185 ktr_sysinit(void *dummy)
 186 {
 187         struct ktr_cpu_core *kcpu;
 188         int i;
 189
 190         for(i = 1; i < ncpus; ++i) {
 191                 kcpu = &ktr_cpu[i].core;
 192                 kcpu->ktr_buf = kmalloc(KTR_ENTRIES * sizeof(struct ktr_entry),
 193                                         M_KTR, M_WAITOK | M_ZERO);
 194         }
 195         callout_init(&ktr_resync_callout);
 196         callout_reset(&ktr_resync_callout, hz / 10, ktr_resync_callback, NULL);
 197 }
 198 SYSINIT(ktr_sysinit, SI_BOOT2_KLD, SI_ORDER_ANY, ktr_sysinit, NULL);
 199
 200 /*
 201  * Try to resynchronize the TSC's for all cpus.  This is really, really nasty.
 202  * We have to send an IPIQ message to all remote cpus, wait until they
 203  * get into their IPIQ processing code loop, then do an even stricter hard
 204  * loop to get the cpus as close to synchronized as we can to get the most
 205  * accurate reading.
 206  *
 207  * This callback occurs on cpu0.
 208  */
 209 #if KTR_TESTLOG
 210 static void ktr_pingpong_remote(void *dummy);
 211 static void ktr_pipeline_remote(void *dummy);
 212 #endif
 213
 214 #if defined(SMP) && defined(_RDTSC_SUPPORTED_)
 215
 216 static void ktr_resync_remote(void *dummy);
 217 extern cpumask_t smp_active_mask;
 218
 219 /*
 220  * We use a callout callback instead of a systimer because we cannot afford
 221  * to preempt anyone to do this, or we might deadlock a spin-lock or
 222  * serializer between two cpus.
 223  */
 224 static
 225 void
 226 ktr_resync_callback(void *dummy __unused)
 227 {
 228         int count;
 229
 230         KKASSERT(mycpu->gd_cpuid == 0);
 231
 232 #if KTR_TESTLOG
 233         /*
 234          * Test logging
 235          */
 236         if (ktr_testlogcnt) {
 237                 --ktr_testlogcnt;
 238                 cpu_disable_intr();
 239                 logtest(test1);
 240                 logtest(test2);
 241                 logtest(test3);
 242                 logtest_noargs(test4);
 243                 logtest_noargs(test5);
 244                 logtest_noargs(test6);
 245                 cpu_enable_intr();
 246         }
 247
 248         /*
 249          * Test IPI messaging
 250          */
 251         if (ktr_testipicnt && ktr_testipicnt_remainder == 0 && ncpus > 1) {
 252                 ktr_testipicnt_remainder = ktr_testipicnt;
 253                 ktr_testipicnt = 0;
 254                 lwkt_send_ipiq_bycpu(1, ktr_pingpong_remote, NULL);
 255         }
 256
 257         /*
 258          * Test critical sections
 259          */
 260         if (ktr_testcritcnt) {
 261                 crit_enter();
 262                 crit_exit();
 263                 logtest_noargs(crit_beg);
 264                 for (count = ktr_testcritcnt; count; --count) {
 265                         crit_enter();
 266                         crit_exit();
 267                 }
 268                 logtest_noargs(crit_end);
 269                 ktr_testcritcnt = 0;
 270         }
 271
 272         /*
 273          * Test spinlock sections
 274          */
 275         if (ktr_testspincnt) {
 276                 struct spinlock spin;
 277
 278                 spin_init(&spin);
 279                 spin_lock_wr(&spin);
 280                 spin_unlock_wr(&spin);
 281                 logtest_noargs(spin_beg);
 282                 for (count = ktr_testspincnt; count; --count) {
 283                         spin_lock_wr(&spin);
 284                         spin_unlock_wr(&spin);
 285                 }
 286                 logtest_noargs(spin_end);
 287                 logtest_noargs(spin_beg);
 288                 for (count = ktr_testspincnt; count; --count) {
 289                         spin_lock_rd(&spin);
 290                         spin_unlock_rd(&spin);
 291                 }
 292                 logtest_noargs(spin_end);
 293                 ktr_testspincnt = 0;
 294         }
 295 #endif
 296
 297         /*
 298          * Resynchronize the TSC
 299          */
 300         if (ktr_resynchronize == 0)
 301                 goto done;
 302         if ((cpu_feature & CPUID_TSC) == 0)
 303                 return;
 304
 305         /*
 306          * Send the synchronizing IPI and wait for all cpus to get into
 307          * their spin loop.  We must process incoming IPIs while waiting
 308          * to avoid a deadlock.
 309          */
 310         crit_enter();
 311         ktr_sync_count = 0;
 312         ktr_sync_state = 1;
 313         ktr_sync_tsc = rdtsc();
 314         count = lwkt_send_ipiq_mask(mycpu->gd_other_cpus & smp_active_mask,
 315                                     (ipifunc1_t)ktr_resync_remote, NULL);
 316         while (ktr_sync_count != count)
 317                 lwkt_process_ipiq();
 318
 319         /*
 320          * Continuously update the TSC for cpu 0 while waiting for all other
 321          * cpus to finish stage 2.
 322          */
 323         cpu_disable_intr();
 324         ktr_sync_tsc = rdtsc();
 325         cpu_sfence();
 326         ktr_sync_state = 2;
 327         cpu_sfence();
 328         while (ktr_sync_count != 0) {
 329                 ktr_sync_tsc = rdtsc();
 330                 cpu_lfence();
 331                 cpu_nop();
 332         }
 333         cpu_enable_intr();
 334         crit_exit();
 335         ktr_sync_state = 0;
 336 done:
 337         callout_reset(&ktr_resync_callout, hz / 10, ktr_resync_callback, NULL);
 338 }
 339
 340 /*
 341  * The remote-end of the KTR synchronization protocol runs on all cpus except
 342  * cpu 0.  Since this is an IPI function, it is entered with the current
 343  * thread in a critical section.
 344  */
 345 static void
 346 ktr_resync_remote(void *dummy __unused)
 347 {
 348         volatile int64_t tsc1 = ktr_sync_tsc;
 349         volatile int64_t tsc2;
 350
 351         /*
 352          * Inform the master that we have entered our hard loop.
 353          */
 354         KKASSERT(ktr_sync_state == 1);
 355         atomic_add_int(&ktr_sync_count, 1);
 356         while (ktr_sync_state == 1) {
 357                 lwkt_process_ipiq();
 358         }
 359
 360         /*
 361          * Now the master is in a hard loop, synchronize the TSC and
 362          * we are done.
 363          */
 364         cpu_disable_intr();
 365         KKASSERT(ktr_sync_state == 2);
 366         tsc2 = ktr_sync_tsc;
 367         if (tsc2 > tsc1)
 368                 tsc_offsets[mycpu->gd_cpuid] = rdtsc() - tsc2;
 369         atomic_subtract_int(&ktr_sync_count, 1);
 370         cpu_enable_intr();
 371 }
 372
 373 #if KTR_TESTLOG
 374
 375 static
 376 void
 377 ktr_pingpong_remote(void *dummy __unused)
 378 {
 379         int other_cpu;
 380
 381         logtest_noargs(pingpong);
 382         other_cpu = 1 - mycpu->gd_cpuid;
 383         if (ktr_testipicnt_remainder) {
 384                 --ktr_testipicnt_remainder;
 385                 lwkt_send_ipiq_bycpu(other_cpu, ktr_pingpong_remote, NULL);
 386         } else {
 387                 lwkt_send_ipiq_bycpu(other_cpu, ktr_pipeline_remote, NULL);
 388                 lwkt_send_ipiq_bycpu(other_cpu, ktr_pipeline_remote, NULL);
 389                 lwkt_send_ipiq_bycpu(other_cpu, ktr_pipeline_remote, NULL);
 390                 lwkt_send_ipiq_bycpu(other_cpu, ktr_pipeline_remote, NULL);
 391                 lwkt_send_ipiq_bycpu(other_cpu, ktr_pipeline_remote, NULL);
 392         }
 393 }
 394
 395 static
 396 void
 397 ktr_pipeline_remote(void *dummy __unused)
 398 {
 399         logtest_noargs(pipeline);
 400 }
 401
 402 #endif
 403
 404 #else   /* !SMP */
 405
 406 /*
 407  * The resync callback for UP doesn't do anything other then run the test
 408  * log messages.  If test logging is not enabled, don't bother resetting
 409  * the callout.
 410  */
 411 static
 412 void
 413 ktr_resync_callback(void *dummy __unused)
 414 {
 415 #if KTR_TESTLOG
 416         /*
 417          * Test logging
 418          */
 419         if (ktr_testlogcnt) {
 420                 --ktr_testlogcnt;
 421                 cpu_disable_intr();
 422                 logtest(test1);
 423                 logtest(test2);
 424                 logtest(test3);
 425                 logtest_noargs(test4);
 426                 logtest_noargs(test5);
 427                 logtest_noargs(test6);
 428                 cpu_enable_intr();
 429         }
 430         callout_reset(&ktr_resync_callout, hz / 10, ktr_resync_callback, NULL);
 431 #endif
 432 }
 433
 434 #endif
 435
 436 /*
 437  * KTR_WRITE_ENTRY - Primary entry point for kernel trace logging
 438  */
 439
 440 static __inline
 441 void
 442 ktr_write_entry(struct ktr_info *info, const char *file, int line, __va_list va)
 443 {
 444         struct ktr_cpu_core *kcpu;
 445         struct ktr_entry *entry;
 446         int cpu;
 447
 448         cpu = mycpu->gd_cpuid;
 449         kcpu = &ktr_cpu[cpu].core;
 450         if (kcpu->ktr_buf == NULL)
 451                 return;
 452
 453         crit_enter();
 454         entry = kcpu->ktr_buf + (kcpu->ktr_idx & KTR_ENTRIES_MASK);
 455         ++kcpu->ktr_idx;
 456 #ifdef _RDTSC_SUPPORTED_
 457         if (cpu_feature & CPUID_TSC) {
 458 #ifdef SMP
 459                 entry->ktr_timestamp = rdtsc() - tsc_offsets[cpu];
 460 #else
 461                 entry->ktr_timestamp = rdtsc();
 462 #endif
 463         } else
 464 #endif
 465         {
 466                 entry->ktr_timestamp = get_approximate_time_t();
 467         }
 468         entry->ktr_info = info;
 469         entry->ktr_file = file;
 470         entry->ktr_line = line;
 471         crit_exit();
 472         if (info->kf_data_size > KTR_BUFSIZE)
 473                 bcopy(va, entry->ktr_data, KTR_BUFSIZE);
 474         else if (info->kf_data_size)
 475                 bcopy(va, entry->ktr_data, info->kf_data_size);
 476         if (ktr_stacktrace)
 477                 cpu_ktr_caller(entry);
 478 #ifdef KTR_VERBOSE
 479         if (ktr_verbose && info->kf_format) {
 480 #ifdef SMP
 481                 kprintf("cpu%d ", cpu);
 482 #endif
 483                 if (ktr_verbose > 1) {
 484                         kprintf("%s.%d\t", entry->ktr_file, entry->ktr_line);
 485                 }
 486                 kvprintf(info->kf_format, va);
 487                 kprintf("\n");
 488         }
 489 #endif
 490 }
 491
 492 void
 493 ktr_log(struct ktr_info *info, const char *file, int line, ...)
 494 {
 495         __va_list va;
 496
 497         if (panicstr == NULL) {
 498                 __va_start(va, line);
 499                 ktr_write_entry(info, file, line, va);
 500                 __va_end(va);
 501         }
 502 }
 503
 504 #ifdef DDB
 505
 506 #define NUM_LINES_PER_PAGE      19
 507
 508 struct tstate {
 509         int     cur;
 510         int     first;
 511 };
 512
 513 static  int db_ktr_verbose;
 514 static  int db_mach_vtrace(int cpu, struct ktr_entry *kp, int idx);
 515
 516 DB_SHOW_COMMAND(ktr, db_ktr_all)
 517 {
 518         struct ktr_cpu_core *kcpu;
 519         int a_flag = 0;
 520         int c;
 521         int nl = 0;
 522         int i;
 523         struct tstate tstate[MAXCPU];
 524         int printcpu = -1;
 525
 526         for(i = 0; i < ncpus; i++) {
 527                 kcpu = &ktr_cpu[i].core;
 528                 tstate[i].first = -1;
 529                 tstate[i].cur = (kcpu->ktr_idx - 1) & KTR_ENTRIES_MASK;
 530         }
 531         db_ktr_verbose = 0;
 532         while ((c = *(modif++)) != '\0') {
 533                 if (c == 'v') {
 534                         db_ktr_verbose = 1;
 535                 }
 536                 else if (c == 'a') {
 537                         a_flag = 1;
 538                 }
 539                 else if (c == 'c') {
 540                         printcpu = 0;
 541                         while ((c = *(modif++)) != '\0') {
 542                                 if (isdigit(c)) {
 543                                         printcpu *= 10;
 544                                         printcpu += c - '0';
 545                                 }
 546                                 else {
 547                                         modif++;
 548                                         break;
 549                                 }
 550                         }
 551                         modif--;
 552                 }
 553         }
 554         if (printcpu > ncpus - 1) {
 555                 db_printf("Invalid cpu number\n");
 556                 return;
 557         }
 558         /*
 559          * Lopp throug all the buffers and print the content of them, sorted
 560          * by the timestamp.
 561          */
 562         while (1) {
 563                 int counter;
 564                 u_int64_t highest_ts;
 565                 int highest_cpu;
 566                 struct ktr_entry *kp;
 567
 568                 if (a_flag == 1 && cncheckc() != -1)
 569                         return;
 570                 highest_ts = 0;
 571                 highest_cpu = -1;
 572                 /*
 573                  * Find the lowest timestamp
 574                  */
 575                 for (i = 0, counter = 0; i < ncpus; i++) {
 576                         kcpu = &ktr_cpu[i].core;
 577                         if (kcpu->ktr_buf == NULL)
 578                                 continue;
 579                         if (printcpu != -1 && printcpu != i)
 580                                 continue;
 581                         if (tstate[i].cur == -1) {
 582                                 counter++;
 583                                 if (counter == ncpus) {
 584                                         db_printf("--- End of trace buffer ---\n");
 585                                         return;
 586                                 }
 587                                 continue;
 588                         }
 589                         if (kcpu->ktr_buf[tstate[i].cur].ktr_timestamp > highest_ts) {
 590                                 highest_ts = kcpu->ktr_buf[tstate[i].cur].ktr_timestamp;
 591                                 highest_cpu = i;
 592                         }
 593                 }
 594                 if (highest_cpu < 0) {
 595                         db_printf("no KTR data available\n");
 596                         break;
 597                 }
 598                 i = highest_cpu;
 599                 kcpu = &ktr_cpu[i].core;
 600                 kp = &kcpu->ktr_buf[tstate[i].cur];
 601                 if (tstate[i].first == -1)
 602                         tstate[i].first = tstate[i].cur;
 603                 if (--tstate[i].cur < 0)
 604                         tstate[i].cur = KTR_ENTRIES - 1;
 605                 if (tstate[i].first == tstate[i].cur) {
 606                         db_mach_vtrace(i, kp, tstate[i].cur + 1);
 607                         tstate[i].cur = -1;
 608                         continue;
 609                 }
 610                 if (kcpu->ktr_buf[tstate[i].cur].ktr_info == NULL)
 611                         tstate[i].cur = -1;
 612                 if (db_more(&nl) == -1)
 613                         break;
 614                 if (db_mach_vtrace(i, kp, tstate[i].cur + 1) == 0)
 615                         tstate[i].cur = -1;
 616         }
 617 }
 618
 619 static int
 620 db_mach_vtrace(int cpu, struct ktr_entry *kp, int idx)
 621 {
 622         if (kp->ktr_info == NULL)
 623                 return(0);
 624 #ifdef SMP
 625         db_printf("cpu%d ", cpu);
 626 #endif
 627         db_printf("%d: ", idx);
 628         if (db_ktr_verbose) {
 629                 db_printf("%10.10lld %s.%d\t", (long long)kp->ktr_timestamp,
 630                     kp->ktr_file, kp->ktr_line);
 631         }
 632         db_printf("%s\t", kp->ktr_info->kf_name);
 633         db_printf("from(%p,%p) ", kp->ktr_caller1, kp->ktr_caller2);
 634         if (kp->ktr_info->kf_format)
 635                 db_vprintf(kp->ktr_info->kf_format, (__va_list)kp->ktr_data);
 636         db_printf("\n");
 637
 638         return(1);
 639 }
 640
 641 #endif  /* DDB */